import dell optiplex 7020/9020 patch from gerrit
    
    coreboot gerrit patch 55232, patchset 31
    
    the actual board will be enabled in a follow-up patch.
    merging the patch on its own first is better practise,
    to run ./update trees -u coreboot
    
    this way, there won't be a revision that breaks builds,
    due to the idiosyncratic nature of coreboot configuration.
    
    Signed-off-by: Leah Rowe <info@minifree.org>